\begin{tikzpicture}
    \tkzDefPoints{0/0/B, 3/0/C, 4.5/0/G, 1.2/2.5/A, 4.2/2.5/D}
    \tkzDefPointOnLine[pos=0.4](A,B)  \tkzGetPoint{E}
    \tkzDefPointOnLine[pos=0.4](D,C)  \tkzGetPoint{F}

    \tkzDrawPolygon(A,B,C,D)
    \tkzDrawSegments(C,G  E,F)
    \tkzLabelPoints[left](A,B,E)
    \tkzLabelPoints[right](D,F)
    \tkzLabelPoints[below](C,G)
\end{tikzpicture}

